When you are using data collected by other entities, you need to consider how relevant and comparable those data are to yours. For example, what methods have been used to collect the data? Is it comparable with your data? To find out which protocols, or methods, are being used by Indiana Agencies, go to the Purdue Catalog of Monitoring Protocols Used by Indiana Agencies. Never heard of a specific protocol? Go to the National Environmental Methods Index, a website maintained by the U.S. Geological Survey, to decode those elusive method designations and find out how professionals measure water quality parameters. There’s even an estimate of cost associated with each method. As you are perusing these methodologies, consider the sensitivity of the test and which media are collected to perform the test to help determine comparability.

In addition to methods, you’ll want to look at the date the data was collected. Generally IDEM includes data from up to 5 years ago as “current.” However, “old” data is still data – at the very least, it might help to characterize historical conditions.

Beyond water quality data, you can get spatial data layers, such as soils, topography, land-use and NPDES permitted facilities, from several sources.

IndianaMap and other interactive maps and downloadable geospatial data are available through the Indiana Geological Survey. This suite of interactive mapping websites allows users to create custom maps using a variety of geographic, geologic, environmental and demographic content. The maps can be viewed or printed at any scale using only a Web browser. Desktop GIS users may also connect to the map services directly and download the data for use with existing GIS applications.

Purdue hosts the Geographic Information System (GIS) Tools for Watershed Management. This website contains links to several Web-based GIS tools, including an online watershed delineation tool that calculates the watershed area draining to a point selected on an interactive map. Once you have delineated the watershed, you can use other tools on the website to estimate the impervious area, run hydrologic models such as L-THIA or download the data for use in a GIS program.

U.S. EPA's EnviroFacts Data Warehouse is a database that is connected to state databases in many program areas, including permitted dischargers, drinking water facilities, brownfields, hazardous waste sites, grants awarded in area of interest and compliance history. Ignore the note that information from Indiana has been frozen. Aside from the occasional glitch, everything from Indiana should be available in the database.

For those working with interstate watersheds, a particularly helpful tool might be the National Map Viewer from USGS. It includes downloadable data layers from the National Hydrography Dataset (including hydrologic unit codes (HUCs), stream lines, and other hydrologic features) as well as land cover, topo maps and large-scale imagery. Be patient – it takes a few minutes to load.

These are just a few of the tools that are available for finding other data for use in your watershed management efforts. A full listing of watershed inventory resources is available in chapter 3 of the Indiana Watershed Planning Guide [PDF].